1. Field of the Invention
This invention relates to a device for sensing the atmosphere in a regenerative furnace or regenerator such as the type used for a glass making apparatus.
2. Discussion of the Technical Problems
Regenerators of glass making apparatuses, e.g. flat glass making apparatuses, usually include a gas pervious bed of refractory material, such as a stacked arrangement of bricks, sometimes called "checker packing", through which hot exhaust gases are passed during one heating cycle in order to heat the packing. In alternate heating cycles, the flow is reversed and the heat stored in the packing serves to preheat combustion air passing through the regenerator. The regenerators are usually employed in pairs, with one on either side of the combustion chamber. While one regenerator is absorbing heat from the exhaust gas, the other is heating incoming air.
A sensing probe may be mounted in the regenerators above the checker packing to monitor percent of oxygen in the exhaust gas for subsequent control of oxygen content in the combustion chamber and to evaluate combustion efficiency. For example, if the percent of oxygen in the chamber atmosphere is above a predetermined level, the excess oxygen may upset the chemical balance in the combustion chamber. If the percent of oxygen in the chamber atmosphere is below a predetermined level, the combustion in the chamber may be incomplete.
Continuous oxygen sensing probes presently available have a short usable life because of thermal breakage and/or damage when exposed to the temperatures, e.g. between 2300.degree. F. (1260.degree. C.) and 3100.degree. F. (1704.degree. C.) in the combustion chamber and/or regenerators. It would be advantageous, therefore, to provide thermal protection for continuous oxygen sensing probes used in regenerators such as regenerators of flat glass making apparatuses to increase the usable life of the devices.